This invention relates to tote boxes and more particularly to tote boxes made from foldable box blanks and having self locking top rails to hold the blanks in an erected, assembled relationship.
Containers which are returnable/reusable are useful for the transportation, storage, and display of goods in commerce. Such containers, commonly called tote boxes, must be of sufficiently rigid construction to enable safe and damage free transport and storage of goods contained therein. These tote boxes are frequently designed so as to be stacked or mounted in a nesting relation for convenient transportation or storage of the tote boxes. In order to be stackable, the upper edge of the tote box is typically reinforced with a top rail or rim member which is adapted to receive another tote box stacked thereupon.
It is conventional to use a variety of materials for the construction of such tote boxes. Such materials typically consist of corrugated paperboard, corrugated plastic sheet, sheet metal and other such materials which are not sufficiently rigid to support a number of filled tote boxes in stacked relation. Therefore, it is also conventional to reinforce the corners of the tote boxes with structural supports so that a lower tote box of a stack of tote boxes can adequately support the load of the upper tote boxes and goods therein without deformation, possibly resulting in damage to the goods contained therein.
Typically these tote box corner supports and top rails require additional fasteners such as rivets, staples, screws or the like to secure the top rail and the corner support to the box itself. These fasteners add material costs and manufacturing steps to the construction of the tote box thereby resulting in an expensive and difficult to assemble tote box.
One patent which discloses a tote box having corner supports and a top rail which are not held in place with additional fasteners such as rivets, staples, screws or the like is applicant""s U.S. Pat. No. 5,295,632. However, in both embodiments of tote box disclosed in this patent, the tote box blank must have end flaps in order to hold the corner supports in place. The use of end flaps requires additional material to form the box blank, resulting in additional cost to manufacture the tote box.
Additionally in applicant""s U.S. Pat. No. 5,295,632 a unitary top rail is locked over the top edge of the tote box with tabs folded downwardly from the upper edges of the box walls. The tabs engage a hook formed on one of the channel side walls of the top rail. Use of such tabs to lock the top rail onto the top edge of the erected box requires that the width of the downwardly open channel of the top rail be at least twice the thickness of the box blank. Additionally, the thickness of the box blank is limited to material thin enough to fold the material approximately 180xc2x0 to form the tabs extending downwardly from the upper edges of the box walls.
Accordingly, it is a primary objective of the present invention to provide a tote box made from a foldable material too thick to accept a full 180xc2x0 fold but so constructed that the folded box blank, top rail and corner enhancers may be assembled without any fasteners and with a minimum of assembly steps and space.
Another objective of this invention has been to provide a tote box which meets the primary objectives set forth hereinabove and which facilitates the stacking of additional tote boxes thereon without deformation of the tote box.
A further object of the present invention has been to provide a tote box having a self-locking top rail securable to a box made of material of substantial thickness which need not be folded over upon itself to create rail locking tabs.
The present invention is directed to a tote box which is assembled from a foldable box blank, corner enhancers and a self-locking top rail. When folded into the appropriate shape, the box blank is erected into a box having a bottom, two opposed end walls, and two opposed side walls. The end walls and side walls have upper edges defining a top edge of the box. At least two opposed walls each have a groove extending horizontally below the upper edge of the respective box wall. In one preferred embodiment each box wall has a continuous groove extending the length of the respective wall. A pair of opposed walls preferably have holes into which reinforcing hand holds may be inserted to aid in manual handling of a loaded tote box. The box blank is preferably die cut but may be otherwise formed.
To hold the erected box blank in an assembled relationship and to reinforce the top edge of the tote box, a channel shaped top rail extends around the top edge of the tote box. In one embodiment of the present invention, the top rail comprises multiple pieces including a pair of side pieces, a pair of end pieces and four corner pieces. The side pieces are of a first length and the end pieces of a second length, the first length being greater than the second length typically. However, the side and end pieces may be of an identical length. The side and end pieces of the top rail are preferably manufactured from extruded plastic or aluminum. However, these pieces may be constructed of other materials such as steel, for example.
Each of the side and end pieces of the top rail has a downwardly open channel formed between a pair of channel side walls. At least one of the channel side walls has an inwardly extending hook. The inwardly extending hook may be located at the bottom of the channel side wall or spaced upwardly from the bottom of the channel side wall. The downwardly open channel of each of the side and end pieces of the top rail has a width approximately equal to the thickness of the box blank. When the downwardly open channel of the top rail piece is pushed down over the upper edge of one of the erected box walls, the inwardly extending hook engages the groove formed in the box wall, thereby locking the top rail piece over the upper edge of the tote box wall. The side and end pieces of the top rail are also engaged with the corner pieces of the top rail to form a continuous top rail locked over the top edge of the box as the result of the engagement of the inwardly extending hooks of at least two top rail pieces with the grooves of at least two opposed box walls.
The inwardly extending hooks of at least two top rail pieces engage the grooves of at least two box walls thereby securing the top rail over the top edge of the tote box without the need for further fasteners such as screws, rivets, or staples. The side and end pieces of the top rail preferably have a vertical lip which extends upwardly from the rail piece. The vertical lip enables nested stacking of additional tote boxes. A first or upper tote box may be nestably stacked on a second or lower tote box by placing the bottom of the first or upper tote box within the vertical lip of the top rail of the second or lower tote box.
The corner pieces of the top rail are preferably made of molded plastic but may be made of other materials. The corner pieces preferably have a vertical lip like the side and end pieces of the top rail but may lack the lip. Each of the inwardly extending hooks of the side and end pieces of the top rail snaps beneath a portion of the corner pieces of the top rail, further securing the multiple pieces of the top rail together.
Structural corner enhancers reside at each corner of the tote box to hold the erected side and end walls together in an assembled relationship and to stiffen the tote box corners. The corner enhancers provide a load path for the weight of the stacked tote boxes and their contents to be distributed downwardly and thereby provide structural integrity to the tote box and prevent side and end wall deformation. Each corner enhancer has a first and second open leg channel, each open leg channel being formed between a pair of leg channel walls. Each of the open leg channels has a width of approximately the thickness of the box blank so that one of the end walls is frictionally held inside one of the open leg channels of a corner enhancer and one of the side walls is frictionally held inside the other open leg channel of the corner enhancer. In this manner, each corner enhancer functions to join together an end wall and a side wall in an orthogonal or right angle relationship. These corner enhancers hold the side and end walls of the box together, without the need for mechanical fasteners.
In order to assemble the tote box of the present invention the box blank is erected and the side and end walls of the erected box blank inserted into the open leg channels of the corner enhancers. A side edge of each side wall and a corresponding side edge of an adjacent end wall are located inside the open leg channels of each of the corner enhancers in order to hold and maintain the walls in an erect vertical position, orthogonal to each other. Once the box blank has been folded and the walls of the box blank inserted into the open leg channels of the corner enhancers at the corners of the box, the corner pieces of the top rail are then snapped in place over the corner enhancers and the side and end pieces of top rail snapped over the upper edges of the box walls.
In an alternative embodiment of the present invention, the top rail is a unitary member rather than a multiple piece top rail. The unitary top rail is preferably manufactured from a single piece of extruded plastic or aluminum. However, the top rail may be constructed of other materials such as steel, for example, and may be produced using other methods.
In another alternative embodiment of the present invention, a plurality of inserts are fitted inside the downwardly open channel of the top rail between the top rail and the box walls. Each of the inserts has a downwardly directing opening defined by a top and a pair of spaced legs extending downwardly from the top. At least one of the legs has an inwardly extending hook engaging the groove formed in the respective box wall and thereby locking the insert over the upper edge of the box wall. An inwardly extending hook of the top rail engages a ledge extending outwardly from the insert, thereby locking the top rail over the insert. This embodiment enables a top rail having a relatively large downwardly open channel to a box wall of a thickness less than the width of the downwardly open channel of the top rail.
One advantage of the present invention is that the tote box can be assembled rapidly without the need for intermediate fastener joining steps and without the need for multiple rivets or fasteners such as have been conventional in prior art tote boxes as, for example, in the tote box disclosed in the assignee""s own earlier U.S. Pat. No. 5,037,027.
Another advantage of the present invention is that the stackable tote box may be constructed of thicker material more quickly and less expensively than is presently possible in competitive type tote boxes.